PengZheng commented on code in PR #734:
URL: https://github.com/apache/celix/pull/734#discussion_r1510524927
##########
libs/framework/src/bundle_context.c:
##########
@@ -839,7 +841,28 @@ static void
celix_bundleContext_removeServiceTrackerTracker(void *data) {
free(tracker);
}
-static void celix_bundleContext_stopTrackerInternal(bundle_context_t *ctx,
long trackerId, bool async, void *doneData, void (*doneCallback)(void*
doneData)) {
+static void
celix_bundleContext_waitForUnusedServiceTracker(celix_bundle_context_t* ctx,
+
celix_bundle_context_service_tracker_entry_t* trkEntry) {
+ // busy wait till the tracker is not used anymore
+ // note that the use count cannot be increased anymore, because the
tracker is removed from the map
+ struct timespec start = celix_gettime(CLOCK_MONOTONIC);
+ int logCount = 0;
+ while (__atomic_load_n(&trkEntry->useCount, __ATOMIC_RELAXED) > 0) {
+ if (celix_elapsedtime(CLOCK_MONOTONIC, start) >
TRACKER_WARN_THRESHOLD_SEC) {
+ fw_log(ctx->framework->logger,
+ CELIX_LOG_LEVEL_WARNING,
+ "Service tracker with trk id %li is still in use after %i
seconds. "
+ "This might indicate a programming error.",
+ trkEntry->trackerId,
+ logCount * TRACKER_WARN_THRESHOLD_SEC);
+ start = celix_gettime(CLOCK_MONOTONIC);
+ logCount++;
+ }
+ usleep(1);
Review Comment:
With high resolution timer enabled for linux kernel, this will lead to high
CPU usage. Is 1ms/10ms acceptable? I think they may be better.
##########
libs/framework/src/bundle_context.c:
##########
@@ -1058,11 +1082,10 @@ bool celix_bundleContext_useServiceWithId(
const char *serviceName,
void *callbackHandle,
void (*use)(void *handle, void *svc)) {
- celix_service_use_options_t opts = CELIX_EMPTY_SERVICE_USE_OPTIONS;
-
- char filter[64];
- snprintf(filter, 64, "(%s=%li)", CELIX_FRAMEWORK_SERVICE_ID, serviceId);
+ char filter[32]; //20 is max long length
+ (void)snprintf(filter, sizeof(filter), "(%s=%li)",
CELIX_FRAMEWORK_SERVICE_ID, serviceId);
Review Comment:
A long can take value `INT64_MIN`, which need 20 bytes(including `-`). The
total length of the buffer needs to be 1 (`(`) + 10
(CELIX_FRAMEWORK_SERVICE_ID) + 1 (`=`) + 20 (`%li`) + 1 (`)`) + 1 ('\0') = 34
bytes. This modification will lead to gcc warning complaining string truncation.
##########
libs/framework/src/bundle_context.c:
##########
@@ -839,7 +841,28 @@ static void
celix_bundleContext_removeServiceTrackerTracker(void *data) {
free(tracker);
}
-static void celix_bundleContext_stopTrackerInternal(bundle_context_t *ctx,
long trackerId, bool async, void *doneData, void (*doneCallback)(void*
doneData)) {
+static void
celix_bundleContext_waitForUnusedServiceTracker(celix_bundle_context_t* ctx,
+
celix_bundle_context_service_tracker_entry_t* trkEntry) {
+ // busy wait till the tracker is not used anymore
+ // note that the use count cannot be increased anymore, because the
tracker is removed from the map
+ struct timespec start = celix_gettime(CLOCK_MONOTONIC);
+ int logCount = 0;
+ while (__atomic_load_n(&trkEntry->useCount, __ATOMIC_RELAXED) > 0) {
Review Comment:
This needs to be `__ATOMIC_ACQUIRE`, otherwise the destroying of tracker may
seems like happen before this from the service user's point of view.
##########
libs/framework/src/bundle_context.c:
##########
@@ -1396,40 +1420,46 @@ static celix_service_tracker_t*
celix_bundleContext_findServiceTracker(celix_bun
}
if (!entry->tracker && entry->createEventId >= 0) { // tracker not yet
created (async creation)
- if (celix_framework_isCurrentThreadTheEventLoop(ctx->framework)) {
- fw_log(
- ctx->framework->logger,
- CELIX_LOG_LEVEL_DEBUG,
- "Tracker with id %li is not yet created.",
- entry->trackerId);
- }
+ fw_log(
+ ctx->framework->logger, CELIX_LOG_LEVEL_DEBUG, "Tracker with id
%li is not yet created.", entry->trackerId);
+ return NULL;
}
- return entry->tracker;
+ return entry;
}
static size_t
celix_bundleContext_useTrackedServiceWithOptionsInternal(celix_bundle_context_t*
ctx,
long
trackerId,
const
celix_tracked_service_use_options_t* opts,
bool
singleUse) {
- celix_auto(celix_rwlock_rlock_guard_t) lck =
celixRwlockRlockGuard_init(&ctx->lock);
- celix_service_tracker_t* trk = celix_bundleContext_findServiceTracker(ctx,
trackerId);
- if (!trk) {
+ celixThreadRwlock_readLock(&ctx->lock);
+ celix_bundle_context_service_tracker_entry_t* trkEntry =
celix_bundleContext_findServiceTracker(ctx, trackerId);
+ if (trkEntry) {
+ // note use count is only increased inside a read (shared) lock and
ensures that the trkEntry is not freed and
+ // the trkEntry->tracker is not destroyed until the use count drops
back to 0.
+ (void)__atomic_fetch_add(&trkEntry->useCount, 1, __ATOMIC_RELAXED);
+ }
+ celixThreadRwlock_unlock(&ctx->lock);
+
+ if (!trkEntry) {
return 0;
}
+ size_t callCount;
if (singleUse) {
- bool called = celix_serviceTracker_useHighestRankingService(trk,
- NULL,
- 0,
-
opts->callbackHandle,
- opts->use,
-
opts->useWithProperties,
-
opts->useWithOwner);
- return called ? 1 : 0;
+ callCount =
celix_serviceTracker_useHighestRankingService(trkEntry->tracker,
+ NULL,
+ 0,
+
opts->callbackHandle,
+ opts->use,
+
opts->useWithProperties,
+
opts->useWithOwner);
} else {
- return celix_serviceTracker_useServices(
- trk, NULL, opts->callbackHandle, opts->use,
opts->useWithProperties, opts->useWithOwner);
+ callCount = celix_serviceTracker_useServices(
+ trkEntry->tracker, NULL, opts->callbackHandle, opts->use,
opts->useWithProperties, opts->useWithOwner);
}
+
+ (void)__atomic_fetch_sub(&trkEntry->useCount, 1, __ATOMIC_RELAXED);
Review Comment:
This has to be `__ATOMIC_RELEASE`, otherwise use of service may seem like
happen after this from the service stopper's point of view.
##########
libs/framework/src/bundle_context.c:
##########
@@ -1396,40 +1420,46 @@ static celix_service_tracker_t*
celix_bundleContext_findServiceTracker(celix_bun
}
if (!entry->tracker && entry->createEventId >= 0) { // tracker not yet
created (async creation)
- if (celix_framework_isCurrentThreadTheEventLoop(ctx->framework)) {
- fw_log(
- ctx->framework->logger,
- CELIX_LOG_LEVEL_DEBUG,
- "Tracker with id %li is not yet created.",
- entry->trackerId);
- }
+ fw_log(
+ ctx->framework->logger, CELIX_LOG_LEVEL_DEBUG, "Tracker with id
%li is not yet created.", entry->trackerId);
+ return NULL;
}
- return entry->tracker;
+ return entry;
}
static size_t
celix_bundleContext_useTrackedServiceWithOptionsInternal(celix_bundle_context_t*
ctx,
long
trackerId,
const
celix_tracked_service_use_options_t* opts,
bool
singleUse) {
- celix_auto(celix_rwlock_rlock_guard_t) lck =
celixRwlockRlockGuard_init(&ctx->lock);
- celix_service_tracker_t* trk = celix_bundleContext_findServiceTracker(ctx,
trackerId);
- if (!trk) {
+ celixThreadRwlock_readLock(&ctx->lock);
+ celix_bundle_context_service_tracker_entry_t* trkEntry =
celix_bundleContext_findServiceTracker(ctx, trackerId);
+ if (trkEntry) {
+ // note use count is only increased inside a read (shared) lock and
ensures that the trkEntry is not freed and
+ // the trkEntry->tracker is not destroyed until the use count drops
back to 0.
+ (void)__atomic_fetch_add(&trkEntry->useCount, 1, __ATOMIC_RELAXED);
Review Comment:
This use of `__ATOMIC_RELAXED` is indeed correct.
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